1. Field of the Invention
The present invention generally relates to systems and methods for determining a position of output of an inspection system in design data space.
2. Description of the Related Art
The following description and examples are not admitted to be prior art by virtue of their inclusion in this section.
Inspection processes are used at various steps during a semiconductor manufacturing process to detect defects on wafers to promote higher yield in the manufacturing process and thus higher profits. Inspection has always been an important part of fabricating semiconductor devices such as ICs. However, as the dimensions of semiconductor devices decrease, inspection becomes even more important to the successful manufacture of acceptable semiconductor devices because smaller defects can cause the devices to fail. For instance, as the dimensions of semiconductor devices decrease, detection of defects of decreasing size has become necessary since even relatively small defects may cause unwanted aberrations in the semiconductor devices.
Some currently available inspection systems are configured to use user-defined alignment marks on each die row to orient themselves to the wafer. In each swath, individual dies are compared with adjacent dies through constant feedback in order to ensure that each die looks identical. The locations in any given swath are remarkably accurate. That is, if one were to visit the same die relative location on multiple dies of the same swath, then one is likely to find the same feature.
However, an entire swath may be misplaced in relation to a global (design) coordinate system. Defect location accuracy for inspection can be improved drastically if the swath positioning errors relative to design can be computed and eliminated from each swath. There are currently available technologies that can be used to compare wafer images to the underlying design and estimate the swath positioning errors. The main disadvantage of such technologies is that they require a customer or the design owner to provide the device manufacturer and/or wafer inspector with the design files for the devices that are being manufactured. It is difficult and sometimes impossible for a customer or design owner to provide the device manufacturer and/or wafer inspector with design information due to the presence of sensitive intellectual property (IP)-related information in the design files.
Accordingly, it would be advantageous to develop systems and methods for determining a position of output of an inspection system in design data space that do not have one or more of the disadvantages described above.